I seems that my 4 channel relay module is acting the opposite of how I thought it should act. When I do use the Arduino "digitalWrite(relay, HIGH);" essentially turning power on to the relay, the relay switch is open. When I write "digitalWrite(relay, LOW);", it closes. How is that correct? I thought when you energized the coil, the switched closed to complete the circuit, not the other way around.
Electronic – arduino – 4 Channel Relay Module Set to LOW activates relay
arduinorelay
Related Solutions
If the heat came from the output (on the relay) you probably driving too much current through your relay, try add resistance to control the current to acceptable range.
If the heat came from the ICs, double check your module connections.
Note: Can help you better if you provide more information of where the heat came from and a link to the datasheet of the module you purchased.
Every relay has a life expectancy... they are not infinite. You are saying that at 3 hertz you activate it a few million times, that is a lot of activations for a relay.
As you have not provided a part number, for illustrative purposes, I have used a generic one. The datasheet of your relay should have a graph like this one...
As you can see, in this relay particularly, the maximum life operations it can have no more than a million and a half operations...
That type of failure is normal in relays because the contact material starts wearing away with normal operation, and if you operate at the maximum rated load, as you can see in the table, the relay will have no more than 30,000 operating cycles.
I hope this information is clear enough.
Best Answer
The relay module inputs are active low. They are designed to work that way.